As part of biomass energy utilization, attempts have been made to hydrolytically saccharify cellulose or hemicellulose, which are major components of plants such as bagasse and rice straw, and then obtain ethanol from its sugar solution. Ethanol thus obtained is planned to be utilized as part of a fuel by being mixed into an automobile fuel or utilized as an alternative fuel for gasoline.
One of the methods for decomposing cellulosic biomass containing cellulose or hemicellulose into saccharides is a method of hydrolytically saccharifying the cellulosic biomass by utilizing high-temperature and high-pressure supercritical or subcritical water.
One example of the method is as follows: charge a biomass raw material that is a ground product of bagasse, rice straw, or the like (such a biomass raw material may be simply referred to as a “raw material” in the description and claims herein) into a reactor; hydrolytically saccharify the raw material in the reactor to obtain a C5 sugar solution; and then further hydrolytically saccharify a dehydrated cake of the C5 sugar solution in a reactor to obtain a C6 sugar solution. Thereafter, these sugar solutions are fermented and distilled, and thereby ethanol is produced.
However, in the case of using such high-temperature and high-pressure supercritical or subcritical water, the hydrolytic saccharification of cellulose or hemicellulose is completed within a short period of time of several seconds to several minutes since the supercritical or subcritical water has strong oxidizing power.
Therefore, there is a strong demand for a saccharification reaction apparatus that is capable of increasing a saccharification rate by charging a biomass raw material in a suitable condition for such a short-time saccharification reaction into a reactor and hydrolytically saccharifying the biomass raw material efficiently in the reactor.
As a device for feeding this kind of biomass raw material and the like, there is a conventional feeding device configured to feed a to-be-treated object into a pressurized container. This device is configured such that the to-be-treated object in a hollow body provided with drainage means is pushed out of the hollow body by a piston through an opening facing the pressurized container (see Patent Literature 1, for example).
As another conventional art example, there is an injection device configured to feed a to-be-injected object containing slurry and solids into a high-temperature and high-pressure reactor by means of a piston moving inside a cylinder. For the purpose of preventing clogging due to the solids, this device is provided with a spindle extending through a through-hole of the piston (see Patent Literature 2, for example).
As yet another conventional art example, there is a dry feeder configured to cause finely divided solids to fall from a slot of a cylinder by gravity into a load chamber. After causing the solids to fall, the feeder closes the slot of the cylinder, and feeds the solids from the load chamber into a high-pressure reaction container by means of a piston (see Patent Literature 3, for example).